Pipette



Jan.25, 1944. w, T MA HS 7 2,339,870

PIPETTE Filed March 51, 1941 m! a!!! a!!! MIL- INVENTOR M400) 7? MAT/#8BEA. ow V ATTORNEY Patented Jan. 25, 1944 'PIPETTE Waddy T. Mathis,Hamden, Conn., assignor to Clay Adams Co. Inc., New York, N. Y.,-a-co1'-poration of New York Application March 31, 1941, Serial No. 385,973

12 Claims.

This invention relates generally to pipettes and similar laboratoryapparatus. More particularly my invention relates to the type ofpipettes used for transferring or collecting measured quantities orfluids.

" The principal object of my invention is to provide a novel device foruse with pipettes and similar laboratory apparatus by means of which apredetermined constant quantity or quantities of fluid may beautomatically drawn into the pipette and in which such constant quantityof fluid may be altered and regulated, in accordance with desiredrequirements.

Other objects of my'invention will in part be obvious and in parthereinafter pointed out.

In the accompanying drawing Fig. 1 is a front elevational view, partlyin sectionyof a pipette and automatic measuring device constructed inaccordance with my invention;

Fig. 2 is a side elevational view of a portion thereof; and

Fig. 3 is a; vertical sectional view of a portion of the apparatus shownin Fig. 1, and illustrating astepinthe use thereof.

Referring now in detail to the drawing I have shown a pipette or tube IDof the type customarily employed in laboratory work for transferring andcollecting fluids and provided with suitable graduations II formeasuring quantities of fluid drawn into the tube l0.

For creating a suction, in order to draw fluid into the tube I U, Iemploy a collapsible rubber bulb I2 'of any suitable standardconstruction having a bottom aperture I2a communicating with the hollowinterior thereof. The said bulb I2 is connected to the tube ID by meansof a nipple l5 having a tapered projecting portion l5a frictionallyreceived and held in the aperture [2a and having an opening l5 providedwith a resilient lining member I! into which there is frictionallyreceived, the upper end of the tube I 0. An aperture 18 in the nipple l5communieating-with opening l6 and with the hollow interior of the bulbl2, completes the air passage- 20 designed to threadedly receive thereonthe threaded aperture 2[ in the bottom wall 22a of a frame 22'. The saidframe 22 comprises a wall 22b integral with the bottom wall 22a andextending upwardly therefrom in the form of a loop. The said loopsubstantially follows the contour of the outer surface of the bulb and.is of such size as to snugly accommodate the said bulb I2 therein, whenin non-collapsed condition, to form a housing therefor.

The wall 221) is provided with a through aperture 25 into which there isslidably mounted a shaft member 26. A portion of the Wall 221)surrounding the aperture 25 may be provided with an extension 2'! toform a better bearing surface for the shaft 26.

At one end of the shaft 26 and disposed between the inner surface wall22b and the bulb is an enlarged head 28, so constructed and arrangedthat when the shaft 26 is slidably moved inwardly in the direction ofthe arrow A, the bulb [2, held in position by the frame 22, will becollapsed. Upon release of the shaft 26, the normal resilience of thebulb l2 will slidably restore the shaft 26 to its original position asin Fig. l of the drawing and at the same time a suction will be createdto automatically draw fluid into the tube I ii. A suitable finger piece30 may be provided at the opposite end of the shaft 26 from that of theenlarged head 28 to facilitate the sliding movement of the shaft 26.

In accordance with my invention I have provided the following meanswhereby a predetermined and constant amount of fluid may beautomatically drawn into the tube Ill and expelled therefrom, each timethe shaft 26 is slidably moved to collapse and to release the bulb l2.

A portion of the shaft 26 is provided with threads 3| On which there isthreadedly received a pair of nuts 32 and 33. It is therefore seen thatthe shaft 26 may be slidably moved in the direction of the arrow A onlyuntil the nut 32 strikes the wall portion 21. In other words, the lengthof the stroke of the shaft 26 is controlled by the position of the nut32 on the shaft 26. The second nut 33 serves as a locknut to preventdisplacement of the nut 32 from its selected position.

It is also noted that once the position of the nut 32 on the shaft hasbeen selected in accord ance with the amount of fluid it is desired todrawinto the tube Iii, repeated constant quantities of fluid may bequickly and automatically collected in the tube in, by merely pressingthe fmger piece 30, to first slidably move the shaft 26 from theposition shown in Fig. 1 to the position shown in Fig. 3 with the nut 32in abutting relationship with the wall portion 27, and then releasingsaid finger piece, to permit the bulb to expand to its normal size.

In view of the fact that the nuts 32 and 33 are threadedly received onthe shaft 26 the volume of fluid drawn into the tube may be regulated asdesired.

It should be noted that the use of an open frame or housing, such asshown at 22, provides for unrestricted access to the bulb l2, fordrawing into the tube [0, or expelling therefrom, an amount of fluidwhich differs from the amount controlled by the setting of theadjustable nuts 32, 33, without disturbing the setting of the nuts.

It will thus be seen that there is provided a device in which theseveral objects of this invention are achieved, and which is welladapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention,and as various changes might be made in the embodiment above set forth,it is to be understood that all matter herein set forth or shown in theaccompanying drawing is to be interpreted as illustrative and not in alimiting sense.

Having described my invention, I claim as new and desire to secure byLetters Patent:

1. In a laboratory apparatus of the class described, the combination ofa tube, a suction bulb, a member for interconnecting said bulb with saidtube whereby a suction may be created in said tube upon compressing andreleasing said bulb and means supported by said interconnecting memberfor causing said bulb to be compressed, said last named means comprisinga unitary open looped frame for said bulb and a compressor unit mountedon said frame.

2. In a laboratory apparatus of the class described, the combination ofa tube, a suction bulb, a member for interconnecting said bulb with saidtube whereby a suction may be created in said tube upon compressing andreleasing said bulb and means supported by said interconnecting memberfor causing said bulb to be compressed, said last named means comprisinga frame partially enclosing said bulb and a compressor unit mounted onsaid frame, said compressor unit comprising a rod slidably supported insaid frame, said partially enclosing frame permitting direct handcompression of the bulb, without disturbing the compressor unit.

3. In a laboratory apparatus of the class described, the combination ofa tube, a suction bulb, a member for interconnecting said bulb with saidtube whereby a suction may be created in said tube upon compressing andreleasing said bulb and means supported by said interconnecting memberfor causing said bulb to be compressed,

said last named means comprising a unitary openlooped frame for saidbulb and a compressor unit mounted on said frame, said compressor unitcomprising a rod slidably supported in said frame and having an enlargedhead portion adapted to engage said bulb and to compress the same uponsliding movement of said rod.

4. In a laboratory apparatus of the class described, the combination ofa tube, a suction bulb, a member for interconnecting said bulb with saidtube whereby a suction may be created in said tube upon compressing andreleasing said bulb, said member having a recess at one end for thereception of said tube and a projection at the other end for mountingsaid bulb, means supported by said interconnecting member for causingsaid bulb to be compressed, said last named means comprising a unitaryopen looped frame.

for said bulb, a compressor unit mounted on said frame, said compressorunit comprising a rod slidably supported in said frame and having anenlarged head portion adapted to engage said bulb and to compress thesame upon sliding movement of said rod and a finger piece on said rod tofacilitate the sliding movement thereof.

5. In a laboratory apparatus of the class described, the combination ofa tube, a suction bulb, a member for interconnecting said bulb with saidtube whereby a suction may be created in said tube upon compressing andreleasing said bulb, said member having a recess at one end for thereception of said tube and a projection at the other end for mountingsaid bulb, means supported by said interconnecting member for causingsaid bulb to be compressed, said last named means comprising a housingfor said bulb, a compressor unit mounted on said housing, saidcompressor unit comprising a rod slidably supported in said housing andan abutment member on said rod to limit the amount of sliding movementthereof to provide a constant amount of compression of said bulb.

6. In a laboratory apparatus of the class described, the combination ofa tube, a rubber suction bulb, a member for interconnecting said bulbwith said tube whereby a suction may be created in said tube uponcompressing and releasing said bulb, means supported by saidinterconnecting member for causing said bulb to be compressed, said lastnamed means comprising a housing for said bulb and a compressor. unitmounted on said housing, said compressor unit comprising a rod slidablysupported in said 7. In a laboratory apparatus ofthe class described,the combination of a tube, a rubber sucttion bulb, a member forinterconnecting said bulb with said tube whereby a suction may becreated in said tube upon compressing and. re-

leasing said bulb, means supported by said interconnecting member'forcausing said bulb to ill 9. In a laboratory apparatus of the class de-'scribed, the combination according to claim 7 in which said abutmentmember comprises a nut.

threadedly mounted on said rod and in'which the said locking meanscomprises a nutthreadedly mounted on said rod. 10. In a laboratoryapparatus of the class described, the combination according to claim 6,in which the housing only partially encloses the bulb, for direct handmanipulation of the bulb; without disturbing the setting of theadjustable abutment member of the compressor unit.

l1.'In a laboratory apparatus of the class do scribed, the combinationof a removable tube and a pre-assembled compressor unit, said compressorunit comprising a suction bulb, a member for interconnecting said bulbwith said tube, whereby a suction may be created in said tube by thecompressing and releasing of said bulb, said interconnecting memberhaving a recess at one end for the reception of said removable tube anda projection at the other end for mounting said bulb, and meanssupported by said interconnecting member for causing said bulb to becompressed.

12. In a laboratory apparatus of the class described, the combination ofa removable tube and a pre-assembled compressor unit, said compressorunit comprising a suction bulb, a memher for interconnecting said bulbwith said tube, whereby a suction may be created in said tube by thecompressing and releasing of said bulb, said interconnecting memberhaving a recess at one end for the reception of said removable tube anda projection at the other end for mounting said bulb, and meanssupported by said interconnecting member for causing said bulb to becompressed, said last named means including means for limiting theamount of compression of said bulb so that a constant predeterminedquantity of fluid may be drawn into said tube.

WADDY T. MATHIS.

